饱和碱水钻井液技术

安棚碱矿位于南襄盆地泌阳凹陷东南部深凹构造区，天然碱矿叠合面积为10.74km^2，工业会计师约为4985万吨，化学成分主要为Na2CO3和NaHCO3，其中NaHCO3的含量平均为77.06%，Na2Co3的含量平均为16.33%,天然碱矿石主要集中在下第三系核二段和核三段，埋藏深度一般为1500-2500m，围岩以白云岩类，油页岩，泥页岩及细粉砂岩为主，针对安棚碱井使用饱和Na2CO3型碱水钻井液体系存在的碱加量大，钻井液密度高，钻速度低，钻井液成本高等问题，室内优选出了饱和NaHCo3碱水钻井液体系，即（11.0%-13.0%)膨润土 （0.1%-0.3%)FA-367或PAC-141 （1.5%-2.0%)MG-1 (0.5%-1.5%)CMS 13%NaH-CO3 (1.5%-2.0%)SPNH。经现场应用表明，该钻井液体系抑制性强，性能稳定，碱加量少，取出的碱心直径都大于80mm，机械钻速提高了30%，节约了钻井液成本，取全取准了各项资料，满足了碱层钻井施工的要求。

Optimization of the saturated caustic water base drilling fluid

Located in the southeast area of Biyang Saddle in Nangxiang Basin, Anpeng alkali field covers an overlaying area of 10. 74 km2 and has a commercial storage of 49,850,000 tons of alkali. The chemical compositions of the deposit mainly consist of Na2CO3 and NaHCO3, i. e. , 77. 06% of NaHCO3 and 16. 33% of Na2CO3. The alkali deposit locates mainly in the He2 and He3 section of the lower Teriary, between 1500 m to 2500 m in depth. and the adjacent rock consists of dolomite, resinoid shale, mudstone and silty shale. To solve the problems of the saturated Na2CO3 caustic water based drilling fluid used in the alkali wells, e. g. . large adding volume of alkali, heavy mud weight, low ROP, and high drilling fluid cost. etc. . a saturated Na2CO3 caustic water based drilling fluid is presented by laboratory optimization. The system is made up of bentonite (11 % - 13% ) FA-367 or PAC-141 (0. 1%-0. 3%) MG-1(1. 5%-2. 0%) CMS (0. 5%-1. 5%) NaHCO3(13%) SPNH (1. 5%-2.0%). Field using of this system showed its advantages over better shale control, stable performance, and less alkali adding volume. ROP was increased by 30%, and drilling fluid cost was cut down. At the same time, the recovered alkali cores were all 80 mm of diameter, and the geological information was completely and accurately obtained.